In order to permit people with impaired hearing to watch television programs, it is well known to provide closed captions for television programs wherein the spoken dialogue of the television program is superimposed on the video image, similarly to film subtitles. Closed captions are provided for "live" television programs that appear on a daily basis as well as for programs which have been previously recorded. The captions for "live" programs are often created at the time the program is broadcasted, requiring a system by which captions can be inserted into the video signal of a program that is currently being broadcasted.
Under currently practiced technology, captions for many television programs are created in the following way. The live broadcast of a program is viewed by stenographers who type the dialogue from the program into a receiving computer, creating the caption data for the program, for example, in the form of ASCII code. The caption data are then transmitted by a modem from the receiving computer to an encoder. The video signal of the broadcast is also input into the encoder. Upon receiving the video signal and the transmitted caption data, the encoder inserts the caption data into the vertical blanking interval of the video signal. Then the encoder transmits the integrated signal (the video signal plus the caption data) to viewers' home receivers. The receivers then decode the caption data and display the video signal of the program such that the captions appear on the television screen superimposed on the video image.
A method of creating caption data, translating the caption data into a caption signal for insertion into a video signal, and inserting the caption signal into the video signal is described in FIGS. 2A, 2B, and 2C and the description related thereto in U.S. Pat. No. 5,294,982, incorporated herein by reference.
One known organization providing captioning equipment and services is The National Captioning Institute of Falls Church, Va. (hereinafter, NCI). NCI provides caption decoders, such as the Telecaption 4000 decoder, to viewers of television programs who have impaired heating. Moreover, at its Falls Church, Va. and West Coast locations, NCI provides services and equipment for broadcasters for captioning pre-recorded and live broadcasts.
However, due to the number of time zones in the U.S., television programs are frequently broadcasted more than once in a day so that the programs air at a certain time in each of the time zones. For example, if a program is to air at eight o'clock in the evening across the country, the program must be aired four times, once in each time zone. Therefore, in order to provide captioning for these later broadcasts or refeeds of the program, either the captioning process is substantially duplicated or a second generation recording is made of the first broadcast including the inserted captions. This captioning procedure requires a significant amount of operator intervention to accomplish the captioning of the refeeds.
There are a number of known systems for displaying and storing alphanumeric-type dam, such as captions. For example, U.S. Pat. No. 5,097,349 to Nomura et at. discloses a system for storing various types of information including captions with video data onto compact discs. Instruction codes are interleaved with the video data and are used during playback to determine when and how to display the stored information such as captions with the video signal. In another example, U.S. Pat. No. 4,751,578 to Reiter et at., a system is disclosed for processing and displaying closed captions. The caption data is sent in the vertical blanking interval of the program signal and then processed by an RF section and a mixer to place the captioning in a comer box of the video screen format. The mixed signal is then sent to the television for display. However, these systems do not address the specific problems of providing closed captions discussed above.